Efficacy and safety of colistin sulfate in the treatment of infections caused by carbapenem-resistant organisms: a multicenter retrospective cohort study

Background: Polymyxins have become an important treatment option for carbapenem-resistant organisms (CRO) infections. However, there is a rare of clinical studies on colistin sulfate. This study sought to investigate the rate of clinical improvement and adverse reactions of colistin sulfate in the treatment of severe infections caused by CRO in critically ill patients and assess the factors associated with 28-day all-cause mortality.

Methods: This multicenter retrospective cohort study included intensive care unit (ICU) patients who received colistin sulfate due to CRO infections during July 2021 and May 2022. The primary endpoint was clinical improvement at end of therapy. Secondary endpoints included adverse reactions bacterial clearance rate and 28-day all-cause mortality.

Results: A total of 122 patients, who were included between July 2021 and May 2022, were included in this study, of whom 86 (70.5%) showed clinical improvement and 36 (29.5%) showed clinical failure. The comparison of the clinical data of the patients showed that the median sequential organ failure assessment (SOFA) score was higher in the failure group than the improvement group {9.5 [7, 11] vs. 7 [4, 9], P=0.002}, the proportion of patients receiving extracorporeal membrane oxygenation (ECMO) was higher in the failure group than the improvement group (27.8% vs. 12.8%, P=0.046), and the median duration of treatment was longer in the improvement group than the failure group {12 [8, 15] vs. 5.5 [4, 9.75], P<0.001}. A total of 5 (4.1%) patients suffered from acute kidney injury due to increases in creatinine during colistin sulfate treatment. The Cox regression survival analysis showed that the SOFA score [hazards ratio (HR) =1.198, P=0.001], ECMO treatment (HR =2.373, P=0.029), and duration of treatment (HR =0.736, P<0.001) were independently associated with 28-day all-cause mortality.

Conclusions: Colistin sulfate is a reasonable choice for the treatment of CRO infections in the current treatment options are limited. The possible kidney injury caused by the colistin sulfate requires intensive monitoring.